Hydraulic elevator



(Nomoael.)

` T. W. HEERMANS. HYDRAULIC ELBVTOR.

` Patented May 5, 1896.

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HYDRAU LiC ELEVATO R.

SPECIFICATION forming part of Letters Patent No. 559,526, dated May 5,1896.

Appnautn filed May1a1894. sain No. 511,631. on model.)

` at Evanston, in the'county of Cook and State v cated. i i

In the accompanying drawing the gure of Illinois, haveinvented certainnew and useful Improvements in Hydraulic Elevators, of which thefollowing is a specification, reference being had to the accompanyingdrawing.

V The object of my invention is to provide for the certain and gradualstoppage of the car as the piston of the elevator approaches the limitof its stroke. Where high speeds are employed, andes'pecially when `theyare employed in conjunction with high pressures, in order to stop theear automatically at the limits of its travel Without jar it isnecessary that a gradual and exactly-regulated closure of the passagesleading to and fromthe cylinder should be provided. It is also desirabley that when the car is started in the reverse direction no time shouldbe -lost on account of theclosure of such Water-passages- It istheobject of my present invention to provide means for regulating both thestopping and starting of the car, as above indirepresents a verticalcentral section of the cylinder of a hydraulic elevator and so much ofits appurtenances as are necessary to illustrate my invention. y

'A is the cylinder, which may be `of any de-` sired construction. Asshown, it consistsof concentric tubes, the outer tube a being of steeland` the inner tube b of brass. y The in`` termediate layer cbetween'the tubes a and b may be of any desired-material. 'lo thecylinder is secured` the head B by means of bolts ),conne'cting it to athreaded collarD, screwed to the end of the cylinder. v

E is the piston-rlod, to which is aixed the piston F. Said piston, inorder to resist the exceptionally high pressure employedjs pro-` videdwith double-cupped leather packings 45 ff. The piston, however, may beconstructed in any Weihknown manner,` the forms herein shown beingmerely illustrative. i i Forming a part oi? or an extension from thepiston LF a sleeve Gr,..vi1ichis made tapering, as shown, and at itslargest part'iits closely in the cavity ll in the head Il, said cavity',forming a part of theWater-passage leading to and from the cylinder A.The dot-ted outlines at the upper end of II indicate the point at whichthe said passage il leads to the Water supply and discharge passage. y

In the cylinder-head B are formed two auxiliary passages I and J, whichopen at one end into the cylinder and at the other end into the passageIl at a point beyond that to which the sleeve G extends.V The passage Iis provided with lmeans for regulating its effective area, said means,as shown, consisting of a screw K, Whose beveled end forms a valve,seating itself at the bend in the passage I. The passage .I isprovidedwith an inwardlysrs opening check-valve L, normally held to itsforced through the passage I. By properly proportioning the passage I tothe pressure and speeds employed and by means of the' regulating-valve Kthe stoppage of the motion of the piston and the car connected there.

to may be` made as gradual as desired. During the process of y stoppingthe piston there' is an excess of pressurain the cylinder which vtendsto hold the valve L closed; but when the change-valve is shifted so asto introduce' fluid under pressure to the passage II said fluid willopen the valve L and flow through the auxiliary passage I to thecylinder. But for this provision the speed of the piston in startingwould be limited by the amount of fluid which could pass through thepassage I and leak out past the sleeve G,but with the additional`passage .I the reverse movement of the piston is sutliciently rapid.

`For the sake of convenient access I prefer,

especially on small-sized machines employing very high pressure, to makethe auxiliary passages I and J through the cylinder-.head;`

but it is iohvious that the ma be made throug'l'lthepiston Withoutthereby ailiecting the result accomplished or the mode oi aca complishingit. i have indicated such a modication by the dotted lines in thedrawingv and. have designated these passages by the letters and J',respectively.

Vithout eonfmin g myself to the precise details herein shown anddescribed, I claiml. The combination 0f a cylinder having a passage forthe inlet and exhaust of the fluid; the piston therein adapted to closesaid passage when near the liinit of its stroke; auxiliary passages notclosed by the piston and connecting the interior of the cylinder withthe first-named passage; and a check-valve in one of said passagespermitting an infiow to said cyiinder but not a return, substantially asdescribed.

2. The combination of a cylinder having a passage for the inlet andexhaust of the fluid; the piston therein adapted to close said passagewhen near the limit of its stroke; auXiL iary passages not cicsed by thepiston and connecting the interior of the cylinder with the first-namedpassage; means for regulating the flow through one of said passages atwill; and a check-Valve in the other of said passages permitting aniniiow to said cylinder but not a return, substantially as described.

THADDEUS W. HEERMANS.

Witnesses:

V. HUGO, CHAs. B. BOWEN.

